Polyphenylene ethers are a widely used class of thermoplastic engineering resins characterized by excellent hydrolytic stability, dimensional stability, toughness, heat resistance and dielectric properties. They are, however, deficient in certain other properties including workability and flame retardancy. Therefore, there is a continuing search for a means to modify polyphenylene ethers to improve these other properties.
Among the means being studied are blending of polyphenylene ethers with certain other materials including those comprising phosphorus. Nevertheless, molded parts fabricated from such materials generally display degradations in properties including a decrease in glass transition temperatures.
Other means being studied include copolymers of polyphenylene ethers and polysiloxanes. However, such copolymers are often not desirable since methods for producing them are often expensive and result in unstable copolymers which are difficult to process.
It is of increasing interest, therefore, to prepare stable polyarylene ether copolymers which display flame retardancy and are prepared via cost effective methods.